Field of the Invention
The invention relates to a power conversion technique, and more particularly, to an inverting apparatus and a control method thereof.
Description of Related Art
In order to reduce the consumption of fossil fuels, applications of renewable energy have been vigorously developed for the power systems nowadays. The applications may include, for example, a photovoltaic module that generates power by solar energy, a wind power generation module that generates power by wind power, a hydroelectric power generation module that generates power by water flow or other renewable energy generation modules. However, since power is generated from natural resources for all of aforementioned renewable energy generation modules, their output power performance/output capability may be changed dramatically by influences from the environment.
For instance, take a DC current generation apparatus using the photovoltaic module (e.g., solar panel) as an example, variation of external conditions (e.g., weather conditions, a condition where the solar panel is sheltered or other possible conditions) is the major reason that changes the power performance/output capability of a DC power generated by the photovoltaic module.
Because most of the DC power generation apparatuses constituted by the renewable energy generation modules have an issue of unstable output capability, when these DC power generation apparatuses are applied in AC power systems, designs for an inverting apparatus of back-end must be adjusted in response to said issue. Otherwise, if the inverting apparatus of back-end fails to instantly respond to the changes in the power performance of the DC power generation apparatus of front-end (e.g., when a difference between an input voltage and a command voltage is too large), it often results in a system outage caused by the input voltage of the inverting apparatus which fails to follow the overly large command voltage.